For over half a century the major environmental legislation and regulatory framework has been built in the U.S. during periods when both parties shared governance, and many important environmental laws were signed by Republican presidents. The table below is a selected list of significant advances in federal environmental law from 1970 to 2016 and provides an indication of which party was in power in the Executive and Legislative branches of the federal government. This list is not meant to imply strong bipartisan support on all accounts, and amendments and policies that weaken the laws are not included. The purpose of this list is to demonstrate that many important milestones occurred during administrations headed by both parties and often with different parties in power in the Executive and Legislative branches of government.
This timeline begins with Earth Day, which triggered political action resulting in the most comprehensive body of environmental legislation in the world.Â
20 million people participated in the first Earth Day in the U.S. in 1970 - this was approximately 10% of the U.S. population at the time (203,392,031 total) and is the largest single-day protest in U.S. history.